u_math.h: fix 64 to 32 bit truncation warning
u_math.h: fix 64 to 32 bit truncation warning

Signed-off-by: Alon Levy <816c907b754fa7b5d4bb5eb91e0fc01e5510e64d@redhat.com>
Reviewed-by: Brian Paul <3cb4e1df5ec4da2c7c4af7c52cec8cf340a55a10@vmware.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler